﻿#region License
/* ---------------------------------------------------------------- *
 *
 * This file is part of the API Concepts Framework
 * http://apiconceptsframework.codeplex.com
 *
 * Copyright (C) 2014 eva Kühn, Thomas Scheller, Vienna University of Technology
 * http://www.complang.tuwien.ac.at/eva
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see http://www.gnu.org/licenses/
 *
 * ---------------------------------------------------------------- */
#endregion

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using ApiConceptsFramework.Contract;

namespace ApiConceptsFramework.Concepts.Properties
{
	public class NumberOfMembersWithSamePrefix : IMeasurableProperty
	{
		internal const int NumberOfMembersForSuggestingReduction = 10;
		internal const float NumberOfMembersToComplexityFactor = 0.5f;
		
		public float CalculateComplexity(MeasurableTarget target, IDE ide = IDE.VisualStudioOrSimilar)
		{
			//TODO different handling for visual studio and eclipse (+ overloads in eclipse)

			var membersWithSamePrefix = GetMembersWithSamePrefix(target).Distinct(m => m.Name);
			var membersBefore = GetMembersBefore(membersWithSamePrefix, target.Member);
			CalculationInfo = membersBefore.Count + " members with same prefix before this one: " + string.Join(", ", membersBefore);
			return membersBefore.Count * NumberOfMembersToComplexityFactor;
		}

		public IEnumerable<string> GetSuggestions(MeasurableTarget target, IDE ide = IDE.VisualStudioOrSimilar)
		{
			var membersWithSamePrefix = GetMembersWithSamePrefix(target).Distinct(m => m.Name);
			var membersBefore = GetMembersBefore(membersWithSamePrefix, target.Member);

			if (membersBefore.Count >= NumberOfMembersForSuggestingReduction)
				yield return "There is a high number of members " + membersBefore.Count + " with the same prefix as " + target.Member.Name +
				             " listed before this member, which may make it hard to discover in the code completion window. Consider renaming or removing members.";
		}

		public string CalculationInfo { get; private set; }

		public IEnumerable<MemberInfo> GetMembersWithSamePrefix(MeasurableTarget target)
		{
			var prefix = (target.Member.Name.Length) > 3 ? target.Member.Name.Substring(0, 3) : target.Member.Name; //TODO find a better way to compare prefix than just using first 3 letters??
			return target
				  .GetMembersForComplexityCalculation(target.Member.IsStatic())
			      .Where(m => m.Name.StartsWith(prefix, StringComparison.OrdinalIgnoreCase));
		}

		public List<string> GetMembersBefore(IEnumerable<MemberInfo> members, MemberInfo member)
		{
			return members.OrderBy(m => m.Name).TakeWhile(memberBefore => member.Name != memberBefore.Name).Select(m => m.Name).ToList();
		}
	}
}